Diane Modahl has won leave to appeal to the House of Lords in her legal battle with the British Athletic Federation over drug-taking allegations.

The 31-year-old former Commonwealth 800m champion has been challenging the effectiveness of sampling procedures at a Portuguese laboratory where a 1994 specimen of her urine tested positive in 1994.

She has already cleared her name of the allegations and won the right to sue the federation for £1 million damages over her claims that there had been bias at the disciplinary hearings.

But she was barred by the Court of Appeal last year from pursuing the federation to court over her allegations that the Lisbon laboratory where the drug test was carried out was not accredited by international athletic bodies. She has now won the right to challenge that ruling.

Her four-year ban from running was lifted by the International Amateur Federation after an appeal tribunal found there were doubts about the accuracy of the tests.